Lighting structures vary widely and accordingly with the applications in which they are utilized. In residential situations, for example, regular low-power lighting is sufficient to light the target area. In other situations, however, such as television studios, high-powered industrial lighting structures are needed. In these studio-type situations, high-powered lighting is utilized to project light onto the subject being filmed or photographed. By providing enhanced lighting, i.e., bright light, the camera is able to focus and clearly depict the subject matter.
Traditionally, brighter lighting means higher-power bulbs, higher energy consumption, and a corresponding increase in heat produced by the light. In fact, in many commercial studio lighting structures, a person cannot safely stand within 3 feet of the light without experiencing a physical discomfort or actual harm from the heat being radiated from the device. Fortunately, at least in film or photography studios, many of these lights are attached to the ceiling, placing them out of reach from most people. However, the increased heat being radiated into the atmosphere must be compensated for by cooling the building or room in which the lighting structure is being used. Therefore, these high-power bulbs are not only are dangerous and expensive to purchase, but end up greatly increasing operating costs in both energy consumption of the lights and in cooling costs for the area. Also, in applications where the lighting structures cannot be placed out of contact from people, such as on-location shoots, the intensely-hot lights provide a constant safety concern.
One application that particularly suffers from the shortcomings of the prior art is the surgical environment. In an operating room, the temperature should remain cool to prevent disease and bacteria from spreading. At the same time, bright lights are needed to light the surgery area. Prior-art bright lights produce heat and are often located in close proximity to the surgeon's head, causing him or her to sweat and/or be uncomfortable. The heat also raises the temperature in the operating room.
Recently, light emitting diode (LED) structures have begun appearing in myriad applications. This is partly because LED lights use dramatically less power than traditional bulbs and, as a result, also produce very little heat. In addition, the lifespan of an LED bulb greatly exceeds that most known prior-art light bulbs. For these reasons, it is becoming clear that LEDs will soon be a viable option for completely replacing most bulbs as lighting elements within the home and elsewhere.
Several entities have experimented with utilizing LEDs in studio lighting structures. Because LEDs do not produce the output of standard light bulbs, in particular, the high-powered studio lights, multiple LEDs, organized in arrays, are utilized to replace each bulb. One example of such a light 100 is shown in FIG. 1, which includes an array 101 of individual LED light sources 102a-n (where a-n represents any number range from 1 to infinity) broadcasting light rays 104a-n in the direction of a subject 106 being lit. Unfortunately, the light rays 104a-n produced by each LED in the array 101 hit the subject 106 at a unique angle, which produces a multitude of shadows with varying intensities on the background 108. More specifically, the light from some of the light sources 102a-n in the array 101 reach the background and are additive, thereby producing a first shadow intensity level 110. This first intensity level 110 is also dependent on the proximity between the radiating light source 102 and the background 108. On other portions of the background 108 a different number of the light sources 102a-n in the array 101 reach the background and produce a second shadow intensity level 112, which is different from the first shadow intensity level 110. FIG. 1 provides only a two-dimensional depiction of this multi-shadow effect. With a three-dimensional subject, the differences in shadow intensities are greatly enhanced. The adjacent multiple shadows are not only unattractive, but are sometimes rather eerie looking. For at least this reason, LED light arrays have not been well received in a studio lighting situation.
Although LEDs generate less heat than typical traditional light bulbs, they, nevertheless, do generate heat. Currently-known LED studio lighting structures require the presence of one or more fans that constantly run and pull air from the environment into the lighting structure and across a set of heat dissipating heat-sink fins. These fans require energy, add weight and cost to the lighting device, provide a point of potential electrical failure (which can serious damage the remaining components that will become too hot), and create noise.
LED lighting devices and systems have come into widespread use in homes and buildings. Known LED structures for regular ambient lighting currently dissipate heat by exposing one or more portions of the LED structure to atmospheric conditions. Some known LED lighting assemblies also expose portions, e.g., the power supply 120 and/or driver/controller circuit 118, if applicable, to the atmosphere as those portions of LEDs also generate heat. In addition, a limited number of LED lighting assemblies have one or more heat sinks 116 attached thereto to facilitate the dissipation of heat through convection. However the form, and although having a generally longer life than traditional bulbs, these known LEDs, when ran for normal periods of time, experience a drastic reduction in bulb intensity.
This is specifically applicable when LED lighting assemblies are obstructed or placed in enclosed spaces where hot air is not easily exchanged with cooler air. One example of this is LED lighting structures placed within a recessed lighting “can.” When an LED light is placed within small or enclosed areas, the space surrounding the LED bulbs is not cooled and much of the generated heat from the bulbs remains in that area. This effect is shown in FIG. 2, which illustrates a prior-art LED lighting assembly 200 within a recessed portion 204 of a ceiling 202. The hot air, represented with arrows 206, is not effectively dissipated and continually subjects the assembly 200 to air at high temperatures. As the LED assembly 200 is continually subjected to high temperatures, the lifespan of the assembly 200 is reduced and the probability of heat-related malfunctions is increased. This also renders any heat sinks 208 coupled to those prior-art assemblies 200 to be ineffective and inefficient as they still suffer from the same problems as described above, i.e. the LED assembly 200 is still subjected to previously dissipated heat.
Furthermore, as LED lighting technology is still being developed or has increased manufacturing costs, when compared to those prior-art lighting assemblies, those costs are generally placed on the consumer. As such, LED lighting assemblies can range anywhere from three to ten times more per unit price than for traditional lighting assemblies, such as incandescent light bulbs. Many users dilute those additional initial up-front costs with the continued energy savings associated with LEDs. Therefore, most users desire to maintain the LED lighting assembly lifespan as long as possible to maximize cost efficiency.
In addition, recessed lighting cans within ceilings, particularly in residential settings, include varying dimensions. More particularly, such cans have varying depths between the height of the socket for the bulb and the level of the ceiling. Lighting fixtures currently provided have various distances between the sockets, which accept the bulbs and the ceiling heights. This makes little or no difference if a bulb is inserted. However, if there is a retrofit or new light which is applied and which needs to be flush or partially flush with the ceiling, fixed length shafts between the fixed socket and the lighting appliance are inconvenient. Therefore, for lighting fixtures that are intended to hang relative to the cans at a desired position relative to the ceiling, users must select a lighting fixture with a desired length, which cannot be selectively varied to accommodate differently dimensioned recessed lighting cans.
Therefore, a need exists to overcome the problems with the prior art as discussed above.